Closed breech gun



Dec. 28, 1965 'G. R. KRUZELL.

CLOSED BREECH GUN 2 Sheets-Sheet Filed July 15, 1964 INVENTOR fifOZGE/F.K5025 ,1/ ,M, mz 171% Z] M ATTORNEYS United States Patent Filed July 15,1964, Ser. No. 382,864 9 Claims. (Cl. 89187) This invention relates toimprovements in a firearm of the type provided with a closed breech.

It is an important object of the invention to provide such a firearmwhich is particularly adapted for use in the firing of either rockettype missiles or projectiles, in which the booster or propellant chargeneed not be housed within a cartridge case, but may be in the form ofsolid self sustaining material preferably bonded or secured to themissile to therewith constitute a single complete ammunition round orunit. In either such use, it will be apparent that the breech closingmechanism of the gun constitutes the sole means for preventing rearwarddischarge of a gas blast which, if permitted, would seriously endangerthe gunner, and would involve serious risk of premature ignition ofammunition in the magazine of the gun.

With these considerations in mind, the present invention utilizes as itsbreech closure mechanism a sliding bolt having the firing pin guidedtherein for operative projection and includes mechanism for positivelylocking both the bolt and firing pin in their forwardly projectingposition in gas tight sealing relation with respect to the breechopening.

It is a further important object of the invention to provide such a gunwhich is incapable of firing unless the bolt has first been locked inits forwardly projected position so that, in the event of failure of thebolt locking member or mechanism, there is provided a fail-safe factor.

It is a still further object to prevent actuation of the firing pinuntil it also is blocked from premature rearward movement by gaspressures created by the firing of the weapon.

In order to achieve these ends, the invention incorporates a novel modeof operation in accordance with which a locking and actuating membercommon to both the bolt and the firing pin is automatically projectedtransversely to and rearwardly of both the bolt and the firing pin, orportions thereof, as the bolt is seated in its fully projected position.The arrangement is such that the said member arrives first in locking orobstructing position with respect to the bolt, and subsequently actuatesthe firing pin by quick forward projection thereof, while simultaneouslyentering into locking engagement therewith to prevent retraction of thefiring pin before the firing is substantially completed.

The locking and actuating member and the firing pin have mutuallycooperating cam means, through which the firing pin is both projectedand locked against retraction. In the preferred embodiment of theinvention, the locking engagement between the bolt and the locking andactuating member also is achieved by mutually cooperating cam meanswhich serve additionally to urge the bolt firmly forwardly into sealingrelation with respect to the breech opening. The cam means may thusassist the bolt actuating spring in firmly and fully projecting the boltto its operative sealing position, whereby to provide increased forcefor urging oversize or misshaped ammunition into the firing chamber.

It is a still further object of the invention to provide such a gunwhich is capable of fully automatic firing in the manner of a machinegun, and which at the same time requires a greatly reduced number ofparts having a simplified mode of assembly and operation.

It is a further feature of the invention that such a weapon is alsocapable of firing either as a semiautomatic gun or as a single shot gun.

3,225,657 Patented ec. 28, 1965 In this application there is shown anddescribed only the preferred embodiment of the invention together withminor modifications of certain of its details, and specific language isused in describing same. However, it will be understood that thedrawings and description are merely by way of exemplification ratherthan limitation of the invention.

In the accompanying drawings:

FIGURE 1 is a vertical medial section through the firing mechanism of ashoulder type firearm embodying the invention, with the parts in theoperative positions which they assume in firing a round of ammunition.

FIGURES 2 and 3 are sections on the lines 22 and 3-3 respectively ofFIGURE 1.

FIGURE -4 is an enlarged section, taken in the same plane as FIGURE 1,through the receiver and the adjacent portion of the gun barrel.

FIGURE 5 is a fragmentary view generally similar to FIGURE 4, but withthe bolt retracted, and with a fresh. round of ammunition positioned inthe receiver for delivery into the firing chamber by the return orprojection movement of the bolt.

Referring now in detail to the preferred embodiment of the invention, asspecifically illustrated in the accompanying drawings:

The firearm there illustrated comprises a generally conventional gunbarrel 10 formed with a bore 11 therethrough which defines a firingchamber 12 at its rear end and terminates rearwardly in a breech openingdefined by a rearwardly presented conical sealing surface 13. The bore11 may, if desired, be rifled in conventional manner (not shown) forimparting spinning stabilizing movement to a projectile p of a round ofammunition R loaded into the firing chamber through the breech opening13. The round of ammunition here illustrated also includes a propellantcharge of explosive c which may consist of conventional gun powder inwhich the grains are bonded together by a suitable adhesive and also areadhesively or otherwise secured to the projectile p. It is contemplatedthat the charge 0 will have sutficient strength and shape maintainingqualities as to permit elimination of the usual metal cartridge or shellcasing. By eliminating the shell casing or cartridge, with itsassociated expense, it is also possible to eliminate from the gunstructure the usual means or mechanisms for extracting and ejecting thecasings or expended cartridges after firing, though such mechanism ormeans may, if desired, be included, as hereinafter more specificallydescribed.

The rounds of ammunition R may also represent rocket type or reactionmissiles, in which event the barrel 10 may be provided with suitablepressure release ports and passages, in accordance with known practice,as exemplified in U.S. Patents Nos. 2,802,399 and 2,515,180.

Means defining the breech opening 13 are exemplified by the bushing 15functioning in effect as a rearward extension or portion of the barrel,but in the present instance formed of a somewhat softer metal such asbronze whereby to effect an improved and substantially conformingsealing engagement with the bolt 16. A hollow receiver 17 is rigidlyconnected to the barrel with its interior bolt well 18 aligned with thebore 11. In the present embodiment the forwardly opening end of thereceiver 17 snugly receives and is shrink fitted, threaded on orotherwise suitably secured to the barrel. With this arrangement, thebushing 15 at the rear end of the barrel also is housed within thereceiver.

The weapon of the preferred embodiment is of a sufficiently small sizethat it may be employed as a shoulder gun, and for this purpose itincludes a supporting stock 20 having at its forward end an adapterpiece 21 received within and closing the rear end of the receiver as at22 and so firmly secured therein as by the attaching means or cross pin23. If desired, the stock may be firmly anchored to the adapter 21 bymeans of the reinforcing rod 24 extending lengthwise through the stockand having its forward end 25 threaded into a bore within the adapter.

The bolt 16, which exemplifies the breech closing mechanism of thepresent embodiment, is guided in the bolt well 18 of the receiver formovement in alignment with the bore 11 and its breech opening 13.Preferably the bolt 16 is of a generally cylindrical cross sectionalshape proportioned and arranged for free sliding movement within thebolt well 18 between its rearwardly retracted position, as shown inFIGURE 5 and its forwardly projected position, as shown in full lines inFIGURES 1 and 4. At its forwardly directed end, the bolt 1p is providedwith a reduced diameter tapered nose 27 defining a generally forwardlyconverging sealing surface for operative fiush sealing engagement withthe sealing surface 13 around the breech opening. Preferably the sealingsurfaces 13 and 27 are conically tapered in a forwardly convergingmanner and at identical angles, whereby to achieve efficient sealingaction over a wide area of engagement.

For urging the bolt 16 from its retracted position toward its projectedoperative sealing position there is provided a usual bolt return spring30, here exemplified as a coil spring axially compressed between thebolt operating handle 31 and the blind end of a bore 32 in the receiverwithin which one end of the spring is guided and housed. The other endof the spring may be supported on and located by a guide pin 33 affixedto the bolt handle 31. The bolt handle will be seen to projectexternally of the receiver through a longitudinal slot 34 so that itsexternal end may be grasped and pulled rearwardly to manually retractthe bolt 16 to substantially the position shown in FIGURE 5.

For releasably retaining or latching the bolt in this retractedposition, there is provided a sear 35 which is guided for movement intoand from engagement with the bolt through an opening 36 in the receiver.The inner end of the sear 35 is formed to present an inclined camsurface 37 presented for operative engagement by the bolt during itsretraction movement to automatically urge the sear transverselyoutwardly through its guide opening 36 and thus out of obstructionrelation with respect to the rearwardly moving bolt.

The bolt is formed with a forwardly presented locking face 38 forholding or cocking engagement by the sear incident to retraction of thebolt. By abutting engagement with the forwardly presented locking face38 of the bolt, the sear will then releasably latch the bolt in itsretracted and cocked position. Selective disengagement of the sear 35from the bolt for firing of the weapon, is under the control of aconventional trigger 4b, pivoted at 41 to the receiver and having adepending lever arm 42 operatively connected to the sear 35 through thepin and slot connection 43. The trigger is normally urged to itsinoperative position by means of a conventional coil spring 4 (shown inFIGURE 1), under compression between the trigger 40 and the receiver. Itwill be apparent that the spring 44 also acts through the trigger andits connection to the sear 35 to resiliently urge the latter into thebolt well 18 for operative latching engagement with the bolt.

The bolt 16 is formed with a firing pin guide passage 45 having apreferably reduced diameter portion or section 45A opening through itsforward end toward the breech opening 13 and firing chamber 12. A firingpin 46 is guided for movement in the passage 45 with its striker 47snugly slidably received and guided through the reduced diameter passagesection 45A for projection forwardly into operative engagement with theprimer or ignitor I of a round of ammunition R in the firing chamber 12,whereby to ignite same by percussion in known manner.

Sealing means 49 and 5-0 respectively, in the form of interengagingconical sealing surfaces, are provided respectively on the firing pin 45and within the bolt 16, for operative sealing engagement in theoperative firing position of the firing pin. These provide an efiicientgas tight seal preventing rearward discharge of gases through thepassage 45 so long as the firing pin 46 is held forwardly in itsprojected position. As shown in FIGURES 4 and 5, the sealing surface 49in the present embodiment is provided by the conically taperedtransition portion of the firing pin 46 between its reduced diameterstriker 4'7 and its relatively larger diameter midportion 51. Theconically tapered sealing surface 5%) within the bolt preferably isdefined by a bushing of bronze or other soft metal 52 inserted in thefiring pin guide passage 45 as shown. The firing pin 4-6 is guided inthe guide passage by a generally cylindrical pilot portion 4-? snuglyslidable in said passage.

Normally the firing pin 46 is resiliently urged toward its retractedposition by a spring 53 disposed under compression on the midsection 510f the firing pin in endwise abutment with the bushing 51 and with thefiring pin shoulder 54 at the forward end of the pilot portion 48 of thefiring pin. The rearward projection movement of the firing pin 46 isaccurately predetermined and limited in eXtent by suitable means such asillustrated in FIG- URE 4, comprising a set screw 55 threaded throughthe bolt with its inner end slidably received within a slot 56 in thefiring pin to limit the retraction of the latter by abutting engagementwith the forward end of the slot 56. The length of the slot 56 willobviously be such as to permit operative projection movement of thefiring pin to the full extent desired.

The mechanism for locking both the bolt 16 and the firing pin 46 intheir forwardly projected sealing positions during firing, as well asfor actuating the firing pin to drive it forward into its projectedposition, includes a locking and actuating member 57 common to andcooperating with both elements 16 and 46. The member 57 is guided in abearing sleeve 58 for linear movement into and from the receivertransversely to and across the paths of movement of the firing pin 46and bolt 16 to engage behind rearwardly presented portions 60 and 61respectively of these members whereby to prevent their retractionmovement. A set screw 59, as shown in FIG- URES 4 and 5, limits theprojection movement of the member 57, the inner end of the set screwbeing received in a slot in member 57 as shown. The locking andactuating member 57 is constantly urged inwardly into operativeengagement with the bolt 16 and firing pin 4-6 by means of its actuatingspring 62 which is compressed between the member 57 and a suitablespring seat 65 at the lower end of bearing sleeve 58. t will beunderstood that the bearing sleeve is suitably fixed to and functions asa stationary part of the receiver 17.

The rearwardly presented portion 60 of the firing pin is exemplified byan inclined or sloping cam surface which is adapted for cammingengagement by the upwardly projected member 57. The slope of the camsurface 60 is sufficient to produce rapid projection of the firing pininto detonating engagement with the primer or ignitor I of an ammunitionround within the firing chamber 12, and thus is normally greater thanthat of the cam surfaces 61 and 63.

Because of the location of the firing pin 45 within and surrounded bythe bolt, it will be apparent that before the member 57 can engage andcommence the actuation of the firing pin, it will have had to extend atleast partially across the path of rearward retraction movement of thebolt to obstruct or block such movement. After the locking and actuatingmember 5'7 as advanced far enough to project the firing pin forwardlyinto firing position, it will also be disposed in obstructing andblocking or locking relation rearwardly of the firing pin to preventretraction thereof.

In the preferred embodiment, the rearwardly presented portion 61 of thebolt is in the form of an inclined cam face or surface for cooperativeengagement with the similarly inclined cam surface 63 on the member 57.This one surface 63 in the present embodiment, is relied upon both forits camming function with respect to the bolt as well as for lockingengagement with the bolt.

It will be seen that the portions 60 and 61 of the firing pin and boltrespectively, together with the inclined surface 63 of the locking andactuating member 57, exemplify cooperating cam means on the several suchelements for successively urging and locking the bolt against retractionfrom its projected position, and for then operatively projecting oractuating the firing pin. In addition, the cam surface 63 serves toaugment the action of the bolt spring 30 in firmly urging the bolttoward its fully seated position in sealing engagement with the sealingsurface 13 which defines the breech opening. In the event the forwardprojection of the bolt is arrested before the latter is substantially infully projected breech closing position, the bolt in turn will arrestthe upward projection movement of the member 57 before the latter canactuate the firing pin 16. Similarly, in the event of malfunctioning orfailure of the member 57 or its spring 62, the firing pin will not beactuated and the weapon will thus not be fired.

In order to permit retraction of the bolt 16 for loading or reloading ofthe weapon it is necessary to retract the member 57 from its lockingposition. Where the gun is to be employed as a single shot weapon, thelocking and actuating member 57 may be manually retracted by suitableactuation of its release rod 64, hereinafter more fully described.

In order that the locking and actuating member 57 may not arrest orunduly obstruct the projection movement of the bolt 16 as same travelsfrom its retracted and cooked position shown in FIGURE 5, to itsforwardly projected breech closing position shown in full lines inFIGURES 1 and 4, the locking and actuating member is provided with arearwardly and upwardly presented gently inclined cam surface 67 forcamming engagement with the forwardly presented tapered nose 27 of thebolt. The engagement between these two cam surfaces obviously effectsretraction of the member 57 to an inoperative and nonobstructingposition at one end of the bolt, incident to the forward movement of thelatter past member 57.

The release rod 64 for member 53 is provided at its rear end with a camface 65 for operative engagement with a cam face 66 on the member 57, toretract same. Thus rearward movement of the rod 64 through its slidebearings 66 and 67, retracts or disengages the locking and actuatingmember from the firing pin and bolt.

It will be apparent that the structure as described up to this pointwill sufiice for operation of the gun as a single shot weapon. To cockthe gun, it is necessary first to manually retract the locking andactuating member 57 in any suitable manner, for instance by manuallyactuating its release rod 64, while the bolt 16 is retracted and cockedby manual actuation of its handle 31. Single rounds of ammunition may bemanually inserted into the receiver 17 through its loading port 68 tothereafter be moved into the firing chamber and fired by actuation ofthe trigger 49 which disengages the sear 35 from the bolt, with ensuingforward projection of the bolt.

An important aspect of the invention consists in its adaptation foreither fully automatic or semi-automatic firing, by the addition theretoof a conventional ammunition magazine 70, together with means shown inFIG- URE 1, exemplified by the gas cylinder and piston unit 71operatively connected to the locking member 57 through a suitablelinkage, preferably including release rod 64, to automatically retractor disengage the member 57 from both the bolt and the firing pin 16 and'46 respectively, in properly timed relation to the firing of each roundof ammunition. The timing is such as to permit automatic retraction ofthe bolt 16 by residual gas pressure within the barrel 11 and theautomatic loading or delivery of a fresh round of ammunition from themagazine 70 in advance of the bolt during each retraction thereof, inreadiness for movement into the firing chamber and firing on the nextensuing forward projection of the bolt.

As above mentioned, the magazine 70 is of usual type adapted to containa plurality of rounds R of ammunition (though but one such round isshown) and having a follower 72 urged upwardly by a spring 73 forconveying the rounds of ammunition successively upwardly into thereceiver.

The gas cylinder and piston unit 71 has its cylinder in communicationwith the bore 11 of the barrel by means of a passage 74 appropriatelylocated along the length of the barrel to admit gas to the cylinder justbefore the projectile P leaves the barrel, and at a time when theresidual gas pressure Within the bore will be ample to automaticallyretract the bolt 16, but insuflicient to produce a dangerous rearwardblast through the breech opening 13.

The piston 75 of the unit 71 normally is located within its cylinderrearwardly of the gas passage 74, to be forced rearwardly by the gasesadmitted into the cylinder. Its rearwardly projecting piston rod 76 issupported by the piston for endwise abutment with the release rod 64.The rearwardly presented end of the release rod 64 is adapted forprojection into the bearing sleeve 58 through a suitable located openingso that its inclined cam surface 65 may coact with cam surface 66 of themember 57 to depress or retract the latter completely out of the path ofthe bolt 16. A spring 77 normally urges the release rod to its releasedposition.

A plunger 80 guided through the housing of the piston and cylinder unit71, may be manually thrust into endwise abutment with a projecting lug81 on the release rod, to facilitate manual actuation of the latter,though this is not essential.

In the operation of the invention, where it is desired to fire the gunautomatically, the gun is loaded and cocked, after placing a loadedmagazine 70 in operative relation with respect to the loading port 68.Upon retraction of the bolt, the magazine spring 73 automatically feedsa round of ammunition into the receiver in the path of projectionmovement of the bolt 16. The trigger 40 may then be suitably actuated todisengage the retracted bolt, whereby same may move forwardly under theinfluence of its spring 30, ramming the round of ammunition into thefiring chamber 12 and also thrusting the locking member 57 aside by thecamming engagement between said member and its tapered nose 27.

The ensuing spring projection of the locking and actuating member 57serves to cam the bolt forwardly into fully seated sealing position withrespect to the breech opening 13 and actuates the firing pin 46 to firethe round. Just before the fired round leaves the barrel, pressurizedgas from the rear of the projectile P is admitted to the gas piston andcylinder unit 71 through the passage 74, thereby actuating the said unitand its linkage means 76, 77 to automatically retract the member 57 toinoperative position. This permits automatic recoil or retraction of thebolt 16 by residual gas pressure within the barrel, to effect anautomatic reloading from the magazine 70. In the event the trigger 40 isreleased immediately after firing a given round, the rearwardlyprojected bolt will be engaged by the sear 35 and held in cockedposition to be released by a subsequent actuation of the trigger 40 forsemi-automatic firing. However, fully automatic firing may be achievedsimply by maintaining the actuating pull on the trigger 40, therebymaintaining the sear 35 retracted to permit free reciprocation of thebolt and repeated automatic firing, either until the trigger is releasedor until the ammunition is exhausted from the magazine 70.

In the preferred embodiment of the invention, the locking and actuatingmember 57 is disclosed as having but a single cam face 63, forcooperation with both the firing pin 46 and the bolt 16.

However, it will be understood by reference to the modified arrangementof the locking and actuating member 57 as shown in FIGURE 6, that themember 57' may readily be formed with separate cam surfaces 63A and 633respectively, having different slopes for separate engagement with thefiring pin 46 and bolt 16' respectively, the slopes of these surfacesbeing selected to project the firing pin forwardly at a greater speedthan the bolt. It will be appreciated that the bolt 16' in thismodification is provided at its rear end with a vertical slot, forreception of the cam surface 63A which, in this instance constitutes oneface of a projecting rib of the member 57.

It will further be apparent that a weapon in accordance with theinvention may be adapted for automatic firing of ammunition utilizingconventional cartridge casings for housing the propellant charge. Insuch event, it will be necessary only to provide an ejection port in oneside of the receiver, and a conventional medially fulcrumed ejector ofthe type actuated by retraction of the bolt, to eject expended cartridgecasings through such port. The casings will obviously be movedrearwardly by the same gas pressure which automatically retracts thebolt.

I claim:

1. A firearm comprising a barrel formed with a bore therethroughdefining a firing chamber at its rear end and terminating rearwardly ina breech opening, means defining a rearwardly presented sealing surfacearound said breech opening, a receiver operatively connected to saidbarrel, a bolt guided in said receiver for movement in a predeterminedpath between a rearwardly retracted position and a forwardly projectedposition in which a forwardly presented sealing surface on said boltoperatively engages said sealing surface around the breech opening,resilient means for urging said bolt toward its projected position,selectively releasable means for maintaining said bolt in its retractedposition, said bolt being formed with a firing pin guide passagetherethrough opening forwardly toward said breech opening, a firing pinguided in said passage for forward projection and retraction movement,resilient means normally urging the firing pin toward its retractedposition, sealing means on the firing pin and bolt respectively forengagement with each other to seal said passage in the projectedposition of the firing pin, a locking and actuating member guided onsaid firearm for operative movement across the paths of movement of saidbolt and said firing pin, spring means for operatively moving saidmember, cooperating cam means on said member and on said bolt and firingpin respectively, for successively urging said bolt toward its projectedposition and locking it against retraction and for operativelyprojecting said firing pin and locking it against retraction, means forretracting said locking and actuating member to permit retraction andcooking of the bolt, and cooperating means on the bolt and the lockingand actuating member respectively, for moving the said member out of thepath of the bolt during forward projection f the bolt from its retractedposition.

2. A firearm comprising a barrel formed with a bore therethroughdefining a firing chamber adjacent its rear end and terminatingrearwardly in a breech opening, a receiver operatively connected to saidbarrel, a bolt guided in said receiver for movement in a predeterminedpath between a rearwardly retracted position and a forwardly projectedposition, cooperating means associated with said bolt and said barrelrespectively for sealing said breech opening in the projected positionof the bolt, resilient means urging said bolt toward its projectedposition, sear mechanism for releasably latching said bolt in itsretracted position, a trigger operatively associated with the searmechanism for disengaging same from the bolt to permit projection of thelatter by its said resilient means, said bolt being formed with aforwardly opening firing pin guide passage, a firing pin guided in saidpassage for forward projection and retraction, sealing means on thefiring pin and bolt respectively for interengagement to seal saidpassage in the projected position of the firing pin, a locking andactuating member guided on said firearm for operative movementtransversely to and into the paths of movement of said bolt and saidfiring pin, spring means normally urging said member into said paths,cooperating cam means on said member and on said bolt and firing pinrespectively for successively locking said bolt in its projectedposition and then operatively projecting said firing pin and lockingsame in its projected position, means for retracting said locking andactuating member to permit retraction and cocking of the bolt, andCooperating means on the bolt and the locking and actuating memberrespectively for moving the said member out of the path of the boltduring forward projection movement of the bolt.

3. A firearm comprising a barrel formed with a bore therethroughdefining a firing chamber at its rear end and terminating rearwardly ina breech opening, a receiver operatively connected to said barrel, abolt guided in the receiver for movement in a predetermined path betweena rearwardly retracted position and a forwardly projected position,resilient means urging said bolt toward its projectcd position,selectively releasable means for retaining the bolt in its retractedposition, a firing pin carried by said bolt for operative projectionforwardly of the bolt, resilient means carried by the bolt for urgingsaid firing pin toward its retracted position, a locking and actuatingmember guided on said firearm for operative movement transversely acrossthe paths of movement of said bolt and said firing pin, spring means forurging said member in the direction of its operative movement,cooperating cam means on said member and said bolt and firing pinrespectively for successively moving said bolt and then said firing pinto their fully projected positions, means for retracting said lockingand actuating member to permit retraction of the bolt, and meansdefining an operative connection between the bolt and the locking andactuating member for moving the latter out of the path of the boltduring forward projection movement of the bolt from its retractedposition.

4. A firearm as defined in claim 3, in which said operative connectionis defined by cooperating cam surfaces on the bolt and the locking andactuating member respectively.

5. A firearm comprising a barrel formed with a bore therethroughterminating rearwardly in a breech opening, a receiver operativelyconnected to said barrel, a bolt guided in the receiver for movement ina predetermined path between a rearwardly retracted position and aforwardly projected position in which the said bolt closes said breechopening, resilient means urging the bolt toward its said projectedposition, selectively releasable means for latching the bolt in itsretracted position, a. firing pin carried by said bolt for forwardprojection, means for locking the bolt in its forwardly projectedposition and for thereafter projecting said firing pin, said lastmentioned means including a cam member guided in said receiver foroperative movement transversely of and in camming engagement with bothsaid bolt and said firing pin and for subsequent retraction from thepath of movement of said bolt and firing pin, spring means for producingsaid operative movement of said member, and means carried by the boltfor retracting said member from its path during projection movement ofthe bolt.

6. The combination of claim 5, in which said member includes meansmovable across the path of retraction of said bolt before said cammingengagment with the firing pin.

7. In a firearm comprising a barrel formed with a bore therethroughdefining a firing chamber at its rear end and terminating rearwardly ina breech opening, a receiver operatively connected to said barrel, abolt guided in the receiver for movement in a predetermined path betweena rearwardly retracted position and a forwardly projected position,selectively releasable means for retaining the bolt in its retractedposition, a firing pin carried by said bolt for operative projectionforwardly of the bolt, a locking and actuating member guided on saidfirearm for operative movement transversely across the paths of movement of said bolt and said firing pin, spring means for urging saidmember in the direction of its operative movement, cooperating cam meanson said member and said bolt, and cam means operatively connected tosaid firing pin for successively moving said bolt and then said firingpin to their fully projected positions by engagement of said cam meansof the said member with the respective said cam means for the bolt andthe firing pin.

8. In a firearm as defined in claim 7, the combination therewith ofresilient means carried by the bolt for urging said firing pin towardits retracted position.

10 9. In a firearm as defined by claim 8, the further feature inaccordance with which there are provided cooperating cam surfaces onsaid bolt and on said locking and actuating member respectively forretracting the latter member from the path of the bolt incident toforward projection movement of the bolt from its retracted position.

FOREIGN PATENTS 9/1956 Canada. 1/ 1921 Great Britain.

BENJAMIN A. BORCHELT, Primary Examiner.

FRED C. MATTERN, IR., Examiner.

1. A FIREARM COMPRISING A BARREL FORMED WITH A BORE THERETHROUGHDEFINING A FIRING CHAMBER AT ITS REAR END AND TERMINATING REARWARDLY INA BREECH OPENING, MEANS DEFINING A REARWARDLY PRESENTED SEALING SURFACEAROUND SAID BREECH OPENING, A RECEIVER OPERATIVELY CONNECTED TO SAIDBARREL, A BOLT GUIDED IN SAID RECEIVER FOR MOVEMENT IN A PREDETERMINEDPATH BETWEEN A REARWARDLY RETRACTED POSITION AND A FORWARDLY PROJECTEDPOSITION IN WHICH A FORWARDLY PRESENTED SEALING SURFACE ON SAID BOLTOPERATIVELY ENGAGES SAID SEALING SURFACE AROUND THE BREECH OPENING,RESILIENT MEANS FOR URGING SAID BOLT TOWARD ITS PROJECTED POSITION,SELECTIVELY RELEASABLE MEANS FOR MAINTAINING SAID BOLT IN ITS RETRACTEDPOSITION, SAID BOLT BEING FORMED WITH A FIRING PIN GUIDE PASSAGETHERETHROUGH OPENING FORWARDLY TOWARD SAID BREECH OPENING, A FIRING PINGUIDED IN SAID PASSAGE FOR FORWARD PROJECTION AND RETRACTION MOVEMENT,RESILIENT MEANS NORMALLY URGING THE FIRING PIN TOWARD ITS RETRACTEDPOSITION, SEALING MEANS ON THE FIRING PIN AND BOLT RESPECTIVELY FORENGAGEMENT WITH EACH OTHER TO SEAL SAID PASSAGE IN THE PROJECTEDPOSITION OF THE FIRING PIN, A LOCKING AND ACTUATING MEMBER GUIDED ONSAID FIREARM FOR OPERATIVE MOVEMENT ACROSS THE PATHS OF MOVEMENT OF SAIDBOLT AND SAID FIRING PIN, SPRING MEANS FOR OPERATIVELY MOVING SAIDMEMBER, COOPERATING CAM MEANS ON SAID MEMBER AND ON SAID BOLT AND FIRINGPIN RESPECTIVELY, FOR SUCCESSIVELY URGING SAID BOLT TOWARD ITS PROJECTEDPOSITION AND LOCKING IT AGAINST RETRACTION AND FOR OPERATIVELYPROJECTING SAID FIRING PIN AND LOCKING IT AGAINST RETRACTION, MEANS FORRETRACTING SAID LOCKING AND ACTUATING MEMBER TO PERMIT RETRACTION ANDCOCKING OF THE BOLT, AND COOPERATING MEANS ON THE BOLT AND THE LOCKINGAND ACTUATING MEMBER RESPECTIVELY, FOR MOVING THE SAID MEMBER OUT OF THEPATH OF THE BOLT DURING FORWARD PROJECTION OF THE BOLT FROM ITSRETRACTED POSITION.